HSUPA is a technology regarding uplink performance enhancement. HSUPA improves the data transmission rate of the terminal in the uplink direction of the access network by way of efficiently employing the power when the channel condition is good. HSUPA technology follows most characteristics of the conventional wireless communication technology, such as cell selection, synchronization, random access, basic mobility management, etc. The key technique of HSUPA lies in: Hybrid Automatic Repeat Request (HARQ), rapid scheduling of node B, 2 ms short transmission time interval (TTI).
The HSUPA scheduling algorithm decides the uplink data transmission rate of terminal by taking the following information into account: Received Total Wide band Power (RTWP), terminal transmission power, terminal power remaining, terminal cache capacity, traffic and priority and so on, and notifies the terminal of the maximum available uplink power resource by way of the downlink scheduling control signaling of “absolute grant” or “relative grant”, and the power resource limits the maximum uplink data transmission rate of the terminal. In this case, the “absolute grant” provides the maximum uplink power resource available for the terminal and is the enhanced dedicated channel dedicated physical data channel (E-DPDCH)/dedicated physical control channel (DPCCH) power ratio allowed by each HARQ process at the utmost; the “relative grant” represents that the terminal is up-regulated or reduced by one relative value on the basis of the power resource used by the previous one scheduling, and the serving “relative grant” in particular includes three values of: UP, HOLD, and DOWN, and the non-serving “relative grant” in particular includes two values of: HOLD and DOWN. After having received the scheduling, the terminal will calculate one “serving grant”. The “serving grant” is used for representing the maximum E-DPDCH/DPCCH power ratio for data transmission in the activated HARQ process when the Enhanced Dedicated Channel Transport Format Combination (E-TFC) selects an algorithm.
If the terminal receives the “absolute grant”, then the terminal refers to the absolute grant value mapping relationship table 1 shown in Table 1 or refers to the absolute grant value mapping relationship table 2 shown in Table 2 to update the “serving grant”.
TABLE 1Absolute grantvalueIndex number(168/15)2 × 631(150/15)2 × 630(168/15)2 × 429(150/15)2 × 428(134/15)2 × 427(119/15)2 × 426(150/15)2 × 225 (95/15)2 × 424(168/15)2 23(150/15)2 22(134/15)2 21(119/15)2 20(106/15)2 19(95/15)218(84/15)217(75/15)216(67/15)215(60/15)214(53/15)213(47/15)212(42/15)211(38/15)210(34/15)29(30/15)28(27/15)27(24/15)26(19/15)25(15/15)24(11/15)23 (7/15)22Zero grant1Deactivated0
TABLE 2Absolute grantvalueIndex number(377/15)2 × 431(237/15)2 × 630(168/15)2 × 629(150/15)2 × 628(168/15)2 × 427(150/15)2 × 426(134/15)2 × 425(119/15)2 × 424(150/15)2 × 223 (95/15)2 × 422(168/15)2 21(150/15)2 20(134/15)2 19(119/15)2 18(106/15)2 17(95/15)216(84/15)215(75/15)214(67/15)213(60/15)212(53/15)211(47/15)210(42/15)29(38/15)28(34/15)27(30/15)26(27/15)25(24/15)24(19/15)23(15/15)22Zero grant1Deactivated0
For example, the index number of the “absolute grant” received by the terminal is 31, and the absolute grant value mapping relationship table 1 is used, then terminal refers to Table 1 to update the “serving grant”, and the absolute grant value corresponding to the index number 31 in Table 1 is (168/15)2×6, thus the terminal updates the “serving grant” as (168/15)2×6, i.e. the maximum E-DPDCH/DPCCH power ratio for data transmission during the activated HARQ process is (168/15)2×6.
For another example, the index number of the “absolute grant” received by the terminal is 31, and the absolute grant value mapping relationship table 2 is used, then terminal refers to Table 2 to update the “serving grant”, and the absolute grant value corresponding to the index number 31 in Table 2 is (377/15)2×4, thus the terminal updates the “serving grant” as (377/15)2×4, i.e. the maximum E-DPDCH/DPCCH power ratio for data transmission during the activated HARQ process is (377/15)2×4.
If the terminal receives the “relative grant”, then the terminal will update the “serving grant” according to an algorithm of converting relative grant to serving grant. The algorithm of converting relative grant to serving grant in particular is:
a. The terminal refers to Table 3 (scheduling grant table 1) or refers to Table 4 (scheduling grant table 2);
TABLE 3Index numberScheduling grant37(168/15)2 × 636(150/15)2 × 635(168/15)2 × 434(150/15)2 × 433(134/15)2 × 432(119/15)2 × 431(150/15)2 × 230 (95/15)2 × 429(168/15)2 28(150/15)2 27(134/15)2 26(119/15)2 25(106/15)2 24(95/15)223(84/15)222(75/15)221(67/15)220(60/15)219(53/15)218(47/15)217(42/15)216(38/15)215(34/15)214(30/15)213(27/15)212(24/15)211(21/15)210(19/15)29(17/15)28(15/15)27(13/15)26(12/15)25(11/15)24 (9/15)23 (8/15)22 (7/15)21 (6/15)20 (5/15)2
TABLE 4Index numberScheduling grant37(377/15)2 × 436(336/15)2 × 435(237/15)2 × 634(212/15)2 × 633(237/15)2 × 432(168/15)2 × 631(150/15)2 × 630(168/15)2 × 429(150/15)2 × 428(134/15)2 × 427(119/15)2 × 426(150/15)2 × 225 (95/15)2 × 424(168/15)2 23(150/15)2 22(134/15)2 21(119/15)2 20(106/15)2 19(95/15)218(84/15)217(75/15)216(67/15)215(60/15)214(53/15)213(47/15)212(42/15)211(38/15)210(34/15)29(30/15)28(27/15)27(24/15)26(21/15)25(19/15)24(17/15)23(15/15)22(13/15)21(12/15)20(11/15)2
b. When the terminal receives “one serving relative grant” (cell dedicated channel state or cell forward access channel state after conflict resolution), the terminal determines the minimum power ratio greater than or equal to the “reference power ratio” in Table 3 (scheduling grant table 1) or Table 4 (scheduling grant table 2), determines the index number of the minimum power ratio in the table, and marks the index number as “scheduling grant (power ratio)”.
In this case, the “reference power ratio” is the E-DPDCH/DPCCH power ratio selected by E-TFC for which previous one transmission time interval with the same HARQ process as that of this data transmission is used.
When this serving relative grant is “UP”, if the “scheduling grant (power ratio)” is less than “3 step index threshold”, then the terminal updates the “serving grant” as the scheduling grant in the table corresponding to MIN (“scheduling grant (power ratio)”+3, 37) index; and if the “scheduling grant (power ratio)” is less than “2 step index threshold” and greater than or equal to “3 step index threshold”, then the terminal updates the “serving grant” as the scheduling grant in the table corresponding to MIN (“scheduling grant (power ratio)”+2, 37) index; if the “scheduling grant (power ratio)” is greater than or equal to “2 step index threshold”, then the terminal updates the “serving grant” as the scheduling grant in the table corresponding to MIN (“scheduling grant (power ratio)”+1, 37) index.
When this serving relative grant is “DOWN”, then the terminal updates the “serving grant” as the scheduling grant in the table corresponding to MAX (“scheduling grant (power ratio)”−1, 0) index.
c. When the terminal receives one non-serving relative grant, the terminal determines the minimum power ratio greater than or equal to the maximum “reference recorded and stored power ratio” in the Table 3 (scheduling grant table 1) or Table 4 (scheduling grant table 2), determines the index number of the minimum power ratio in the table, and marks the index number as “scheduling grant (recorded and stored power ratio)”.
In this case, the “reference recorded and stored power ratio” is a recorded and stored new value when the E-DPDCH/DPCCH power ratio selected by the E-TFC, for which the previous one transmission time interval with the same HARQ process as that of this data transmission is used, is updated to the new value.
When this non-serving relative grant is “DOWN”, then the terminal updates the “serving grant” as the scheduling grant in the table corresponding to MAX (“scheduling grant (recorded and stored power ratio)”−1, 0) index.
There are two modulation manners used by HSUPA: quadrature phase shift keying (QPSK) and 16 quadrature amplitude modulation (16QAM). In this case, QPSK is a digital modulation manner and are classified as absolute phase shift and relative phase shift, and 16QAM represents the amplitude and phase combination modulation of 16 sample points, and the information quantity of each symbol is 2 times as much as that of QPSK. 16QAM is a digital high order modulation manner, and as compared to the ordinary modulation manner of QPSK, 16QAM can utilize the channel bandwidth more effectively.
In the related art, when the terminal carries out the 16QAM operation, the “serving grant” has to be updated by reference to Table 4 (scheduling grant table 2) in the algorithm of converting relative grant to serving grant.
In the above related art, during engineering application, the following performance problems may appear:
performance problem 1: when the terminal carries out the 16QAM operation, the index number of the “absolute grant” received by the terminal by reference to Table 1 (absolute grant value mapping relationship table 1) is the index number 31, and the index number 31 in Table 1 (absolute grant value mapping relationship table 1) represents that the absolute grant value is (168/15)2×6, thus the terminal updates the “serving grant” as (168/15)2×6, i.e. the maximum E-DPDCH/DPCCH power ratio for data transmission during the activated HARQ process is (168/15)2×6. Subsequently, if the terminal expects to be able to obtain bigger E-DPDCH/DPCCH power ratio to carry out transmission in a higher uplink data transmission rate, (for example, at this moment, the power remaining of the terminal is relatively high, or the cache capacity of the terminal is relatively high), then it only can be done by way of the serving relative grant “UP”, and by reference to Table 4 (scheduling grant table 2), the “serving grant” is updated according to the algorithm of converting relative grant to serving grant, so as to up-regulate the “serving grant” step by step. Every time when one step is regulated, the time length of at least one transmission time interval is required. If it is expected to regulate “serving grant” from (168/15)2×6 to (377/15)2×4, then at least two steps need to be regulated, and the time length of at least two transmission time intervals is required. The HSUPA scheduling is required to be done within the time length of one transmission time interval, and if the processing time length of two transmission time intervals are required, then the processing time delay is increased by one time, which significantly affects the performance, and the terminal cannot be ensured to be responded promptly by way of rapid scheduling.
performance problem 2: when the terminal carries out the 16QAM operation, the index number of the “absolute grant” received by the terminal by reference to Table 2 (absolute grant value mapping relationship table 2) is 2, and the index number 2 in Table 2 (absolute grant value mapping relationship table 2) represents that the absolute grant value is (15/15), thus the terminal updates the “serving grant” as (15/15), i.e. the maximum E-DPDCH/DPCCH power ratio for data transmission during the activated HARQ process is (15/15)2. Subsequently, if the terminal expects to be able to obtain smaller E-DPDCH/DPCCH power ratio to reduce the uplink data transmission rate, (for example, at this moment, the power remaining of the terminal is insufficient, or the cache capacity of the terminal is almost cleared), then it only can be done by way of the relative grant “DOWN”, and by reference to Table 4 (scheduling grant table 2), the “serving grant” is updated according to the algorithm of converting relative grant to serving grant, so as to down-regulate the “serving grant” step by step. Every time when one step is regulated, the time length of at least one transmission time interval is required. If it is expected to regulate “serving grant” from (15/15)2 to (7/15)2, then at least two steps need to be regulated, and the time length of at least two transmission time intervals is required. The HSUPA scheduling has to be done within the time length of one transmission time interval, and if the processing time length of two transmission time intervals is required, then the processing time delay is increased by one time, which significantly affects the performance, and the terminal cannot be ensured to be responded promptly by way of rapid scheduling.
performance problem 3: when the terminal carries out the 16QAM operation, the index number of the “absolute grant” received by the terminal by reference to Table 1 (absolute grant value mapping relationship table 1) is 3, and the index number 3 in Table 1 (absolute grant value mapping relationship table 1) represents that the absolute grant value is (11/15), thus the terminal updates the “serving grant” as (11/15)2, i.e. the maximum E-DPDCH/DPCCH power ration for data transmission during the activated HARQ process is (11/15)2. Subsequently, the terminal expects to obtain smaller E-DPDCH/DPCCH power ratio such as (7/15)2 to reduce the uplink data transmission rate, (for example, at this moment, the power remaining of the terminal is insufficient, or the cache capacity of the terminal is almost cleared). Since at this moment the “serving grant” is already (11/15)2, which is the lowest limit in Table 4 (scheduling grant table 2), the relative grant “DOWN” can no longer be utilized to down-regulate the “serving grant” step by step. At this moment, the scheduling regulation manner of relative grant is invalid.
The essential reasons for the above performance problems are as follows: the boundaries of Tables 1, 2, 3 and 4 are not aligned, the upper limit and lower limit in various tables are different, and the above performance problems appear during the use of bigger value and smaller value.